Electronic appliance comprising a floating circuit carrier

ABSTRACT

An electronic appliance is especially easy to assemble and includes a housing and a circuit carrier which is held in the housing. The circuit carrier is guided in the housing in a displaceable manner and is applied by at least one spring element against a housing abutment which accurately centres the circuit carrier.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/DE2003/003105 which has anInternational filing date of Sep. 18, 2003, which designated the UnitedStates of America and which claims priority on German Patent Applicationnumber DE 102 46 095.7 filed Oct. 2, 2002, the entire contents of whichare hereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to an electronic appliance. Inparticular, it relates to a switchgear appliance, having a housing andan electronic circuit carrier held therein.

BACKGROUND OF THE INVENTION

The circuit carrier provided in an appliance is usually designed in theform of a so-called printed circuit board assembly. This is understoodto be a printed circuit board populated with elements of an electroniccircuit. The elements may include, in particular, indication elements(e.g. light emitting diodes, etc.), setting elements (e.g.potentiometers and switches, etc.) and also connecting elements (e.g.male strip connectors or terminals, etc.). Moreover, the printed circuitboard assembly is often electrically conductively connected to separateelements arranged in the housing, such as e.g. connecting terminals andfurther electronic components, etc.

A simple, in particular easily automatable mounting of the circuitcarrier in the housing is desirable in order to lower production costs.On the other hand, the circuit carrier must be positioned exactly and asfar as possible without any play in the housing in order to allow forthe setting and connecting elements to be readily accessible from thehousing exterior, or to allow for the indication elements to be readilyvisible through corresponding housing openings or housing windows.

In conventional appliances of this type, the circuit carrier is oftenpushed into a rigid housing guide in which it is fixed after assembly ofthe housing. With a rigid guide, however, a play-free mounting of thecircuit carrier is technically impossible to realize or realizable onlywith difficulty.

DE 42 43 656 A1 discloses a carrier material fastening device in whichthe carrier material can be brought to its final mounted position bypressing away a holder with compliant parts laterally with respect tothe mounting device and can be fixed in the position by snapping backthe holder between it and a chassis supporting claw. The carriermaterial can be separated again from the chassis by exerting a lateralpressure on the holder.

DE 196 30 173 A1 discloses a power module having a module lamina which,in order for it to be fixed mechanically, is pressed against aninsulating ceramic area by a housing. Further, in order for it to makeelectrical contact with printed circuit boards, it is acted on byseparate rotary contact springs mounted in the housing.

SUMMARY OF THE INVENTION

An embodiment of the invention is based on an object of specifying anelectronic appliance which can be assembled in a simple manner and/or inwhich the circuit carrier is positioned particularly precisely in thehousing.

Accordingly, the circuit carrier of an electronic appliance of at leastone embodiment, even with the housing closed, may be guided in adisplaceable manner therein and may be acted on against a housing stopby at least one spring element, which simultaneously serves as anelectrical contact element. The circuit carrier may thus be mounted in afloating manner in the housing and the spring contact according to atleast one embodiment of the invention not only may serve for thefloating mounting of the circuit carrier, but at the same time also mayestablish the electrical connection between the circuit carrier and aseparate element, e.g. a contact terminal, etc. Complicated soldering ofthe circuit carrier during assembly is thus superfluous. The or eachspring contact is preferably formed as a resilient pin contact.

The floating mounting of the circuit carrier enables a particularlysimple assembly of the appliance, especially as the circuit carrier caninitially be inserted into the housing guide without any pressure. Thecircuit carrier may be positioned and fixed automatically duringassembly of the housing by the spring element that is prestressed inthis case. When the housing is closed, the spring element can act on thecircuit carrier in such a way that the latter is pressed against ahousing stop that centers the circuit carrier in the desired position.In this way, the circuit carrier may be mounted essentially without anyplay and in a positionally accurate manner between the housing stop andthe spring element.

The circuit carrier, in at least one embodiment, is preferably a printedcircuit board assembly, i.e. in particular formed in a boardlike manner.In this case, the circuit carrier is expediently guided in adisplaceable manner perpendicularly to the board plane in the housing,thereby enabling the circuit carrier to be inserted into the housingguide in a particularly simple manner.

In an advantageous refinement of an embodiment of the invention, theinsertion of the circuit carrier is furthermore facilitated by the factthat the circuit carrier is provided with a guide contour in the form oftwo indentations arranged at opposite side edges which indentationsinteract with corresponding housing projections that protrude into thehousing interior. The housing projections are preferably realized byscrew channels provided in the housing. The screw channels penetratethrough the housing and serve for receiving a respective fastening screwby which the appliance can be screwed onto a carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is explained in more detailbelow with reference to drawings, in which:

FIG. 1 shows, in an exploded illustration obliquely from above, anelectronic appliance with a circuit carrier embodied as a printedcircuit board assembly, and

FIG. 2 shows the electronic appliance in accordance with FIG. 1 in anexploded illustration obliquely from below.

Mutually corresponding parts are provided with the same referencesymbols in the figures.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The electronic appliance 1 shown in the exploded illustration in FIG. 1is a switchgear appliance, by way of example. The appliance 1 includesan insulating housing 2 having a troughlike housing bottom 3 and ahousing cover 4 that can be emplaced thereon. The appliance 1furthermore includes a printed circuit board assembly 5, e.g. aboardlike circuit carrier populated with elements of an electroniccircuit, in particular electronic components 6. The printed circuitboard assembly 5 can be inserted into the housing 2. The components 6include in particular a light emitting diode (LED) 7.

The printed circuit board assembly 5 is furthermore provided with a malestrip connector 8. In this case, the male strip connector 8 correspondswith a socketlike housing opening 9 in the housing cover 4, throughwhich the male strip connector 8 can be contact-connected from thehousing exterior. The light-emitting diode 7 in turn corresponds with ahousing window 10 arranged in the housing cover 4. For entirelysatisfactory functioning of the appliance 1, it is necessary for theprinted circuit board assembly 5 to be positioned precisely with regardto the housing cover 4, in order to ensure that, on the one hand, thelight-emitting diode 7 is arranged in the region of the housing window10 and, on the other hand, the male strip connector 8 is centered withregard to the housing opening 9.

The printed circuit board assembly 5 is furthermore connected to twocontact terminals 11, which are arranged in the housing bottom 3, andfurther electronic components (not specifically illustrated). Thecontact between these separate elements and the printed circuit boardassembly 5 may be established via pin contacts 12 which protrude intothe housing interior from the housing bottom 3 and make contact with theprinted circuit board assembly 5 at the underside 13 thereof.

The appliance 1 is furthermore provided with two fastening screws 14which serve for fastening the appliance 1 to a carrier (notillustrated), for example within a switchgear cabinet. For this purpose,each fastening screw 14 can be inserted into a screw channel 15 thatpenetrates through both the housing cover 4 and the housing bottom 3.

As can be seen in particular from a joint consideration of FIGS. 1 and2, each screw channel 15 is formed by an approximatelyhollow-cylindrical housing projection 16 which protrudes into thehousing interior from the housing cover 4 and abuts on a correspondinghole 17 in the housing bottom 3 when the housing 2 is joined together.

During assembly of the appliance 1, firstly the printed circuit boardassembly 5 is inserted into the housing cover 4 in such a way that it isaccommodated between the two housing projections 16. For this purpose,each longitudinal end 18 of the printed circuit board assembly 5 isprovided with an indentation 19 which serves as a guide contour andintroduction aid and each of which receives a corresponding projection16 in a positively locking manner with play. In other words, with theprinted circuit board assembly 5 inserted, the edge of the indentation19 engages loosely around the circumference of the projection 16 fromthree sides.

The printed circuit board assembly accommodated between the twoprojections 16 is thus pre-fixed with regard to a direction parallel toits board plane. However, the printed circuit board assembly 5 can bedisplaced perpendicularly to its board plane with respect to the housingcover 4.

In a subsequent assembly step, the housing bottom 3 is pushed into thehousing cover 4 in assembly direction R until latching lugs 20 fitted tothe housing bottom 3 latch in corresponding receptacles 21 in thehousing cover 4 and the housing bottom 3 is thereby fixed captively tothe housing cover 4. During this assembly step, each pin contact 12 ispressed against a corresponding contact area 22 arranged on theunderside 13 of the printed circuit board assembly 5. On account oftheir resilient action, the contact pins 12 in this case yield somewhatcounter to the assembly direction R and are prestressed in this caseagainst the printed circuit board assembly 5. When the housing 2 isclosed, on the one hand the electrical contact between the contactterminals 11 and the printed circuit board assembly 5 is thusestablished via the contact pins 12 and the contact areas 22.

Moreover, when the housing 2 is closed, the printed circuit boardassembly 5 is on the other hand mounted in a displaceable manner andthus in a floating manner against the prestress of the contact pins 12.

The printed circuit board assembly 5 is acted on against the housingcover 4 by the prestress of the contact pins 12, the male stripconnector 8 being pressed against the inner edge 23 of the housingopening 9. As a result of the male strip connector 8 resting on thecontour of the inner edge 23, which serves as a housing stop, theprinted circuit board assembly 5 is automatically fixed with pinpointaccuracy and to a good approximation without any play during theassembly of the housing 2.

Exemplary embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. An electronic appliance, comprising: housing; a circuit carrierguidable into the housing in a displaceable manner by a spring contactadapted to act against a housing stop, wherein the spring contact isadapted to interact and make electrical contact with a respectivecontact area of the circuit, the circuit carrier being boardlike andbeing guidable in a displaceable manner perpendicularly with regard tothe board plane thereof, the circuit carrier having a respectiveindentation at two opposite side edges, and a corresponding housingprojection protruding into the housing being accommodated in saidindentation in a positively locking manner.
 2. The electronic applianceas claimed in claim 1, wherein the spring contact is a resilient pincontact.
 3. The electronic appliance as claimed in claim 1 wherein atleast one housing projection is present, and wherein the at least onehousing projection is a screw channel provided for receiving a fasteningscrew.
 4. The electronic appliance as claimed in 1, wherein the housing,adapted to acted on with the circuit carrier against the housing stop bythe spring element, is further adapted to be closed by a housing coverthat is adapted to be emplaced on the axis along which the springelement acts.
 5. The electronic appliance as claimed in claim 4, whereina male strip connector, provided with the circuit carrier and adapted tobe contact-connected outside the housing, is fixable in a correspondingsocketlike housing opening in the emplaced housing cover by the pressureof the spring element onto the circuit carrier.
 6. The electronicappliance as claimed in claim 1, wherein the electronic appliance is aswitchgear appliance.
 7. The electronic appliance as claimed in claim 2,wherein at least one housing projection is present, and wherein the atleast one housing projection is a screw channel provided for receiving afastening screw.
 8. The electronic appliance as claimed in claim 2,wherein the housing, adapted to be acted on with the circuit carrieragainst the housing stop by the spring element, is further adapted to beclosed by a housing cover that is adapted to be emplaced on the axisalong which the spring element acts.
 9. The electronic appliance asclaimed in claim 3, wherein the housing, adapted to be acted on with thecircuit carrier against the housing stop by the spring element, isfurther adapted to be closed by a housing cover that is adapted to beemplaced on the axis along which the spring element acts.
 10. Theelectronic appliance as claimed in claim 7, wherein the housing, adaptedto be acted on with the circuit carrier against the housing stop by thespring element, is further adapted to be closed by a housing cover thatis adapted to be emplaced on the axis along which the spring elementacts.
 11. The electronic appliance as claimed in claim 8, wherein a malestrip connector, provided with the circuit carrier and adapted to becontact-connected outside the housing, is fixable in a correspondingsocketlike housing opening in the emplaced housing cover by the pressureof the spring element onto the circuit carrier.
 12. The electronicappliance as claimed in claim 9, wherein a male strip connector,provided with the circuit carrier and adapted to be contact-connectedoutside the housing, is fixable in a corresponding socketlike housingopening in the emplaced housing cover by the pressure of the springelement onto the circuit carrier.
 13. The electronic appliance asclaimed in claim 10, wherein a male strip connector, provided with thecircuit carrier and adapted to be contact-connected outside the housing,is fixable in a corresponding socketlike housing opening in the emplacedhousing cover by the pressure of the spring element onto the circuitcarrier.